{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Notes11 - Data Warehousing Overview CS245 Notes 11 Hector...

Info icon This preview shows pages 1–17. Sign up to view the full content.

View Full Document Right Arrow Icon
Data Warehousing Overview CS245 Notes 11 Hector Garcia-Molina Stanford University CS 245 1 Notes11
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
CS 245 Notes11 2 Warehousing Growing industry: $8 billion in 1998 Range from desktop to huge: Walmart: 900-CPU, 2,700 disk, 23TB Teradata system Lots of buzzwords, hype slice & dice, rollup, MOLAP, pivot, ...
Image of page 2
CS 245 Notes11 3 Outline What is a data warehouse? Why a warehouse? Models & operations Implementing a warehouse Future directions
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
CS 245 Notes11 4 What is a Warehouse? Collection of diverse data subject oriented aimed at executive, decision maker often a copy of operational data with value-added data (e.g., summaries, history) integrated time-varying non-volatile more
Image of page 4
CS 245 Notes11 5 What is a Warehouse? Collection of tools gathering data cleansing, integrating, ... querying, reporting, analysis data mining monitoring, administering warehouse
Image of page 5

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
CS 245 Notes11 6 Warehouse Architecture Client Client Warehouse Source Source Source Query & Analysis Integration Metadata
Image of page 6
CS 245 Notes11 7 Motivating Examples Forecasting Comparing performance of units Monitoring, detecting fraud Visualization
Image of page 7

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
CS 245 Notes11 8 Why a Warehouse? Two Approaches: Query-Driven (Lazy) Warehouse (Eager) Source Source ?
Image of page 8
CS 245 Notes11 9 Query-Driven Approach Client Client Wrapper Wrapper Wrapper Mediator Source Source Source
Image of page 9

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
CS 245 Notes11 10 Advantages of Warehousing High query performance Queries not visible outside warehouse Local processing at sources unaffected Can operate when sources unavailable Can query data not stored in a DBMS Extra information at warehouse Modify, summarize (store aggregates) Add historical information
Image of page 10
CS 245 Notes11 11 Advantages of Query-Driven No need to copy data less storage no need to purchase data More up-to-date data Query needs can be unknown Only query interface needed at sources May be less draining on sources
Image of page 11

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
CS 245 Notes11 12 OLTP vs. OLAP OLTP: On Line Transaction Processing Describes processing at operational sites OLAP: On Line Analytical Processing Describes processing at warehouse
Image of page 12
CS 245 Notes11 13 OLTP vs. OLAP Mostly updates Many small transactions Mb-Tb of data Raw data Clerical users Up-to-date data Consistency, recoverability critical Mostly reads Queries long, complex Gb-Tb of data Summarized, consolidated data Decision-makers, analysts as users OLTP OLAP
Image of page 13

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
CS 245 Notes11 14 Data Marts Smaller warehouses Spans part of organization e.g., marketing (customers, products, sales) Do not require enterprise-wide consensus but long term integration problems?
Image of page 14
CS 245 Notes11 15 Warehouse Models & Operators Data Models relations stars & snowflakes cubes Operators slice & dice roll-up, drill down pivoting other
Image of page 15

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
CS 245 Notes11 16 Star customer custId name address city 53 joe 10 main sfo 81 fred 12 main sfo 111 sally 80 willow la product prodId name price p1 bolt 10 p2 nut 5 store storeId
Image of page 16
Image of page 17
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern